Posted: Sat Dec 4, 2021 1:51pm
Right - Pete's wife here (the pest controller) don't spray foam filler, they'll just chew through it, you'll need steel to prevent rodent access, weld mesh/chicken wire, much bigger job.
Do you have any plants growing up the outside of the building? they would need to be removed if they're giving 'it' access. (also trellis) Clearing overgrowth/vegetation a meter around your property would also deter them accessing and would allow predators (cats/foxes) access to keep them down. This will also give you access to the perimeter of your building to see if there's any breaks in the outside of your brickwork...
Where do your waste pipes enter/exit the building? check for any gaps around these points, if you can squeeze 2 fingers into a hole, mr ratty can get in there, 1 finger (or a pencil width!) and a mouse can get in.
As Pete said, there needs to be a source of food nearby. Be sure yours and neighbours are keeping waste securely/inaccessible. any bird feeders nearby? they need to be removed.
any traps you set in your attic space need to be against the edge, ideally. 'over the counter' rodenticide can take up to 20 days to kill a rat, if they eat enough of it.
If a rat chews your wiring, it could be more expensive than calling a professional pest controller out.
hope this is helpful (and not to onerous!)
Linda (wife of Pete :) )